1. Field
This disclosure is concerned generally with the purification of products in biological fluids and specifically with the use of enzymes to selectively degrade unwanted substances to a size range that facilitates the removal of the undesirable substances.
2. Prior Art
Enzymes are relatively complex proteinaceous substances produced by living cells and capable of accelerating very specific chemical reactions. Sometimes referred to as biological catalysts, enzymes have long been used in a variety of industrial, medical and laboratory applications. For example, proteolytic enzymes have been used in laundry detergents to help remove proteinaceous stains, thrombolytic enzymes have been used to dissolve blood clots and hydrolytic enzymes have been used as chromogenic labels useful for immunoassays. Enzymes have been used for a variety of applications in solution (free) and in a so-called immobilized form where they are entrapped or attached via ionic or covalent bonds to supporting materials known as carriers or matrices.
It is well known that enzyme use can be optimized by controlling the conditions of their use (e.g. enzymes typically have an optimal pH range). It is also well known that very specific enzymes such as DNA-ASES are available commercially, especially for use in emerging biotechnology applications where such enzymes are used to accurately cut a nucleic acid at a precise point. To date, however, we are unaware of the use of such enzymes in a controlled manner to facilitate a purification process, especially the purification of therapeutic substances expressed in a cell culture. Surprisingly, we have now found that enzymes can now be used in a relatively simple method to facilitate the purification of various substances, especially biologically active substances generated in various cell cultures where nucleic acids may be present as contaminants. Details of our methods are described below.